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Science News has an exploration of the deeper implications of neutrino oscillation, one experimental confirmation of which we discussed last month. "The new findings could even signal a tiny breakdown of Einstein's theory of special relativity. ... MINOS [for Main Injector Neutrino Oscillation Search] found that during a 735-kilometer journey from Fermilab to the Soudan Underground Laboratory in Minnesota, about 37 percent of muon antineutrinos disappeared — presumably morphing into one of the other neutrino types — compared with just 19 percent of muon neutrinos. ... That difference in transformation rates suggests a difference in mass between antineutrinos and neutrinos. ... With the amount of data collected so far, there's just a 5% probability that the two types of particles weigh the same."

This isn't trouble, we already know there are problems with the theory, we just don't have any measurements that give us an idea of how to fix it (of course the theory works well enough in most cases). Any measurements like this that give us something unexpected are great things, they can give us a more accurate picture of how the world is, help the theory become more accurate. Always look for the flaws in your theory, for that is where the greatest discoveries are hidden.

Since every theory is a simplified model, every theory has problems. Sometimes the model works just fine at the resolution and scope for which it is intended (eg: Hooke's Law). It's the cases where you know it's broken within the bounds it should be working for, but you don't know where or why, that are the exciting ones. In the case of relativity, we know it's incompatible with QM at some level that includes gravity but may extend beyond that. We now know that it also has problems with neutrino mass. It may be that relativity can be fixed - at least for neutrinos - but either relativity or QM (or maybe both) =must= break down entirely within their intended scope in a way that is irretrievable. But nobody knows which, when, why or how.

But this is the fun of science! Science would have no purpose if it weren't for the ferreting out of the glitches and flaws in theories, fixing them and testing them to destruction all over again. We learn so little by being right in comparison to what we learn when we're wrong.

But this is the fun of science! Science would have no purpose if it weren't for the ferreting out of the glitches and flaws in theories, fixing them and testing them to destruction all over again. We learn so little by being right in comparison to what we learn when we're wrong.

It did for me. I spent the bulk of my career happily re-working, undoing, enhancing, fixing, and generally making existing systems better and actually enjoyed it more than the new development. I propbably would have made a good archaeologist.

They are wrong on a universal scale. This has been proven, and indeed it is where things like relativity start to come in. We have measured things that go against the predictions that Newton's laws make. That would mean they've been falsified....

So why the hell do we still teach them?

Well because on the scale we normally work on, Newton's laws simply and accurately describe how things works. You can go out yourself and test them in any number of ways and you'll find that as accurate as you want to measure, they are dead on accurate. When dealing with the scale of things humans normally do, they are an excellent set of rules for calculations.

Thus more accurately put they aren't wrong, they are just a simplification that works within certain bounds. They do not fully describe motion and gravitation on every level, in every case. They break down for very large and very small scales. However they are an excellent simplification for anything less than, say, a planet in size and anything above the atomic level. That would include basically everything you are ever likely to work with.

So they are very much correct, all you have to do is put a couple constraints on their use.

Simplified models like that are wonderful too. Even if they don't explain everything, they allow for calculations to be done in an easy fashion on things we care about. Some day we may discover a truly complete law for motion, that covers all cases from the smallest to the largest. at all speeds, in all frames of reference and so on. There may be nothing left out. It also may be several pages of dense calculations. Instead of that, when dealing with a normal, human scale, we'll still use Newton's laws, something you can express in a couple characters and work out in your head if you are good. An exceedingly useful and accurate simplification.

A similar example would be the Ideal Gas law. When you look at it, it is clearly wrong. Reason is you plug in numbers for something like H2O at room temperature and the result is not what you actually get. It does not show it becoming a liquid. Yet again we use it. Why? Because so long as the substance you are talking about is a gas in the temperature and pressure range you are working at, the Ideal Gas law gives you a very easy, highly accurate, way to calculate things about it. It is a simplification, hence why it is called "Ideal Gas" instead of "Real Gas". That doesn't mean that it isn't accurate and useful within some constraints.

So I can see the same being true with relativity. While we have already found cases it doesn't explain (see quantum gravitation), that doesn't mean it isn't useful within certain constraints. As our knowledge progresses, we will know precisely what those are.

I wish I could find the URL now, but I remember reading once about relativity (don't remember now if it was special or general), the author showing how some of the classical mechanics formulas are basically the first few terms of Taylor Polynomials which represented the values given by relativity, so basically, as you said, they are accurate when sufficiently near 0, but the farther you move away from 0, the more the error accumulates without the 'missing' terms. Really wish I could find it now.

this idea. That a theory is just a tool for understanding and predicting reality. As long as you know where and when you can apply this tool and you use it in those circumstances it's a useful thing. (IE a hammer is great when you just need to hammer in a nail and don't expect it to be some super tool that can cut wood, turn a screw, measure an angle, etc.)

That a theory is just a tool for understanding and predicting reality.

But a theory is more than just that, it's a mental model of reality, the context for sensory input. Einstein's General Relativity and Newton's Laws of Motion are fundamentally different: Newton took time and space to be a passive background, while Einstein made spacetime an active participant in events. The two theories don't just differ a little bit on their results, they represent fundamentally different ways of looking at reality.

But in a way your professor was right: a theory is "just a" tool for understanding reality, in the same way as you brains "just" allow you to think.

Actually! I was looking this up at one point for some reason I forget, but:

You cannot explain the yellowish color of gold [wikipedia.org]* without relativity. If you just use classical chemistry, it should be silvery-white, just like silver. It's also the reason why mercury is one of two elements that are liquid at room temperature; relativistic forces screw with the electrons, making them bind more weakly. Although the reasons why these things happen do come from a level outside of your bounds (it has to do with electrons, which are smaller than atoms) the effects are things everyone takes for granted.

Gold would not be golden if it weren't for relativity! I just find that so amazing.

*It's also how you explain the yellowish color of cesium, but that's not something most people are familiar with.

Oh, one other point - a large part of why we teach them in High School and basic undergraduate physics classes is that they don't require a lot of math beyond algebra and trig, and maybe a little calculus (some knowledge of integration and differentiation can still be useful even with Newton's Laws), but when you start looking at the more accurate models of relativity and things, it starts to take knowledge of much more advanced math, which High School students and undergrads(well, most of them anyhow) won't know or understand.

Not to mention all the esoteric stuff that people still do based on Newton's laws. Astronomers even computer simulate collisions of galaxies using classical physics.

But then again, there are times when relativity matters. If you have a fast-moving spacecraft with a radiolink you need to consider things like space contraction and time contraction. Otherwise you will tune your radios wrong. NASA didn't take it into account in the radio module of their Titan lander when they launched it, but were able to fix i

Well, just as we cannot say with certainty that a law that has not yet been unproven is correct, we also cannot say with certainty that a law that has not yet been unproven is incorrect. Assuming the universe operates on some form of natural law (that is, assuming that all events are not entirely random and arbitrary), then the laws of the universe are finite and therefore describable.

The issue is not that we cannot be right, because it is possible that we can find one that is right; the issue, rather, is that we have no way of irrevocably confirming a law. We may only watch the evidence increase while waiting on the possibility of an event that disproves it.

The problem goes a bit deeper than this. CPT invariance is mathematically equivalent to Poincaré invariance. Breaking CPT means breaking symmetry under the Poincaré group (which is basically all translations, relativistic boosts and rotations). This is specially intriguing because particles are defined as irreducible representations of the Poincaré group. In other words, if Poincaré (or CPT) is broken, we cannot define a particle. This is one of the main problems with compatibility betwe

It's already widely known that Relativity is just a model... much like the rest of physics. It's extremely accurate and useful for dealing with many areas, but breaks down somewhat when dealing with very very small things. Hence the great desire to develop a more unified theory! So, the summary is a little bit on the sensationalist side of the street.

It's already widely known that Relativity is just a model... much like the rest of physics. It's extremely accurate and useful for dealing with many areas, but breaks down somewhat when dealing with very very small things. Hence the great desire to develop a more unified theory! So, the summary is a little bit on the sensationalist side of the street.

The research is very important, though!

That's a gross misunderstanding of the problems of relativity.

"Just a model" is not what physicists seek. The aim is to seek laws of physics that are absolute, inviolable, and a complete description of space, time, and mass-energy. Some of our models are basically there, like the "conservation" laws, which are based on rigorous mathematics.

The problem with relativity isn't that it's "just a model", it's that it is explicitly known to be incomplete. It simply doesn't "extend" down to small scales. This was known by Einstein himself, he sought to complete his theory, but failed.

It's already widely known that Relativity is just a model... much like the rest of physics. It's extremely accurate and useful for dealing with many areas, but breaks down somewhat when dealing with very very small things. Hence the great desire to develop a more unified theory! So, the summary is a little bit on the sensationalist side of the street.

The research is very important, though!

That's a gross misunderstanding of the problems of relativity.

"Just a model" is not what physicists seek. The aim is to seek laws of physics that are absolute, inviolable, and a complete description of space, time, and mass-energy. Some of our models are basically there, like the "conservation" laws, which are based on rigorous mathematics.

The problem with relativity isn't that it's "just a model", it's that it is explicitly known to be incomplete. It simply doesn't "extend" down to small scales. This was known by Einstein himself, he sought to complete his theory, but failed.

Sorry, but I'm a mathematician... so everything you physicists do is just a model to me. Ever since I realized (via Goedel) that there aren't even any complete and consistent theories for logic, I sort of figured that there would never be a complete and consistent theory for physics. (Let me know if you find one.) In the mean time, I'm still really impressed with the work physicists do! I really should finish working through Gravitation some day... that's cool stuff.

The more we learn about physics, the more 'pure' our models will get, and the closer we get to stand to those elitist mathematicians. 8)

Yeah, but you'll never even get close to closing the gap. Physicists have a constraint that mathematicians are immune to: To qualify as "physics", your model must be tested against physical reality. Mathematics can be (and very often is) independent of any so-called "reality". A mathematical model can be shown valid even if it is shown not to model anything in our unive

mathematics is just applied logic, and logic is just applied philosophy...... and philosophy is just applied physics...

Kirk: "Everything Harry tells you is a lie. Remember that! Everything Harry tells you is a lie!"

Harry: "Now listen to this carefully, Norman: I AM LYING!"

Norman: "You say you are lying, but if everything you say is a lie then you are telling the truth, but you cannot tell the truth because everything you say is a lie, but... you lie, you tell the truth, but you cannot for you l... Illogical! Illogical! Please explain! You are Human! Only Humans can explain their behavior! Please explain!"

The aim is to seek laws of physics that are absolute, inviolable, and a complete description of space, time, and mass-energy.

I may be stretching beyond my capacity here, but isn't that a pipe dream? Won't any laws of physics will be mathematical formulae? And I thought it was accepted that no significantly powerful mathematical system can be both complete and consistent. It seems to me that a physics laws would be subject to that same limitation. The search for ever finer models is wonderful, important,

Sorry, but I'm a mathematician... so everything you physicists do is just a model to me

Math exists in a vacuum, and most Math researchers attempt to force observations of real life to fit within their formulas, which is just plain wrong. Physics observes real life, and attempts to describe it (using Math).Or in other words, pure Math is essentially worthless until it is applied to the real world... and when you do that, it's not Math it's Physics.

For example, take the commonly known Math equation 1+1=2. This appears to be correct to the Math student, but then the Physics student comes along a

For example, take the commonly known Math equation 1+1=2. This appears to be correct to the Math student, but then the Physics student comes along and says "Umm, exactly HOW do you expect me to believe that 1 apple + 1 orange = 2 slashdot Trolls?". It's how the equation is applied that determines if it is correct or not.

Not a proof because you're mixing units.

No better than trying to convince a math major that 1 + 1 = 2 is wrong because 1 degree of arc + 1 radian of arc does not equal 2 gradients of arc. Or that stating binary 1 plus binary 1 actually equals binary 10 so 1 + 1 = 2 is false.

Propositional logic, first order logic, relevance logic, linear logic, intuitionistic logic, many modal logics, etc. are complete and consistent. What you mean is that first order logic extended with Peano's arithmetic axioms is incomplete as are many second and higher order logics.

Complete and consistent theories for physics are an entirely different kind of thing. Complete would probably mean "it works for everything we know about" and consistent means "we've not found out anything yet that yields a contr

Sorry, but I'm a mathematician... so everything you physicists do is just a model to me. Ever since I realized (via Goedel) that there aren't even any complete and consistent theories for logic, I sort of figured that there would never be a complete and consistent theory for physics. (Let me know if you find one.) In the mean time, I'm still really impressed with the work physicists do! I really should finish working through Gravitation some day... that's cool stuff.

You're right. Physics are one of the fields where science shines best, but still I think they read more into it than they should.

That, still, Relativity may be a model (in the math sense) but it's much more about the ideas (codified into math, of course). The big breakthough of Einstein was not doing the math, but interpreting what was being seen correctly.

Sorry, but I'm a metamathematician.... so everything you mathematicians do is just a model to me.
Göedel's (first incompleteness) theorem does not state that there aren't any complete and consistent theories for logic, it states that any system *complex enough* (it has some requirements to be met to be true) cannot be both complete and consistent.
Anyway I guess (sorry if I don't) I see your point but I don't think you are seeing your parent's, and (unless I missed it) your point is wrong (as in 'non s

Anyway I guess (sorry if I don't) I see your point but I don't think you are seeing your parent's, and (unless I missed it) your point is wrong (as in 'non sequitur', not as in 'not true' (which it might be))

You need to be careful here. When you talk about relativity "not extending down to small scales," you're referring to General Relativity. Special relativity, OTOH, is a fundamental component of Quantum Field Theory.

A chef theorized that there was a counter-part to bacon. We'll call it turkey bacon. We traditionally thought that Turkey Bacon was the direct opposite of Pig Bacon. Where Pig Bacon was delicious, Turkey Bacon was healthy. We decided to do some research on how Turkey bacon and pig bacon is received by the consumer. Recent taste test show that turkey bacon is not, in fact equally as healthy as pig bacon is tasty. This ruins the grand unified theorem of HTB (healthy tasty breakfast).

The only remaining explanation is there might, in fact, be a third type of bacon... i.e. a cow bacon or chicken bacon. If we discover this new type of bacon, it might completely revolutionize the Bacon Lettuce Tomato sandwich.

Except pig bacon is healthy, and delicious. Contrary to USDA guidelines, saturated fat is good for you, and cereals and grains are bad for you. Bacon is, simply put, health food. You just need to avoid orange juice, muffins, or anything else that is going to raise your blood sugar levels and therefore your insulin levels.

Now, admittedly, there are some types of bacon that are dipped in chocolate, or sugar, or pancake batter, or some other evil condiment, but on its own, bacon is a perfectly healthy food.

Nope. His claims are slightly exaggerated, but there is recent research strongly suggesting that the deposition of fatty plaques on the arteries are much more related to calcium and sugar overconsumption, and specifically the "fatty liver" that results from the latter. And now that researchers do make the distinction between trans-fats and naturally occurring saturated fats, they are finding a paucity of evidence implicating the latter in anything. GP has somewhat oversimplified but basically he is corre

Ok. I read the article and I'm still confused. I understand why different mass for particles and their antiparticles would violate CPT, which is obviously major. But I don't see how this violates special relativity. Why does this violate special relativity?

If I recall correctly CPT presumes the correctness of Lorentz invariance. And Lorentz invariance is one of the bedrocks of relativity. In other words CPT comes about from assuming your theory is Lorentz invariant and if CPT were violated it would mean Lorentz invariance is violated as well (check out Physical Review Letters 89: 231602 by Greenberg, O.W, which shows CPT violation implies Lorentz violation).

Well, you see, the modder had to preserve Slashdot CRM ( Correctness, Relevance, Modding) Invariance which states that Comment Correctness, Comment Relevance, and Comment Modding, when assigned a boolean value (e.g if the Comment is factually correct, it is assigned the value of 1, else 0) of 1 or 0, then multiplied together, must never be 1. So, since we had a correct, relevant comment, the modding must be incorrect to preserve the Invariance.

A CPT violation [wikipedia.org] has major implications for the special theory apparently due to what SciBrad said. Is Lorentz invariance similar to Lorentz Covariance? [wikipedia.org] To get closer to why this is relevant to the special theory take a look at the wiki for Lorentz transformation [wikipedia.org].

The Lorentz transformation was originally the result of attempts by Lorentz and others to explain observed properties of light propagating in what was presumed to be the luminiferous aether; Albert Einstein later reinterpreted the transformation to be a statement about the nature of both space and time, and he independently re-derived the transformation from his postulates of special relativity.

Now, IANATP, but this seems core. We are getting back to the Michelson-Morley experiment [wikipedia.org] for god's sake. I always figured the general theory would be the first to show cracks since it has a lot less solid experimental data behind it. But everyone is always going on about how the special theory is one of the most proven theories in all of science. So this could be big. Very big. Of course, it's a lot easier to just massage the data a little or start positing magical new forces to explain the discrepancy:

To save CPT and Einstein's theory -- assuming they need saving -- Ann Nelson of the University of Washington in Seattle favors the introduction of a new force. [wikipedia.org] "It's a less radical idea" than throwing out Einstein's theory of special relativity, she notes. The force Nelson envisions would endow matter with a new kind of charge that would allow it to interact differently with neutrinos than antineutrinos.

It's a lot easier than tossing out your beloved theory or trying to build it up from scratch based on solid scientific evidence to support each individual tenet. I think the latter is what needs to be done, but it will take time. We need to re-figure out what we know absolutely. IOW, what aspects of special relativity are not contradicted by a CPT violation? If the Lorentz Transformation is called into question then so is science fiction's much beloved time dilation [wikipedia.org] And what about the Twins Paradox? [wikipedia.org] Yikes. This could be big. It is exciting when a major (and the special theory is about as major as it gets) scientific theory is contradicted, even in part because it means we could be on the verge of a major discovery. A real discovery based on experiment as opposed to flights of fancy, the angels dancing on pin heads inside the minds of theoretical physicists and then rationalized ex post facto quantitatively with systems of equations. Let us not forget the lesson of Ptolemy's cycles and epicycles. They predicted the motion of the planets better than Copernicus's theory, at least initially. But if Einstein is Ptolemy, who is Copernicus?

It's a lot easier than tossing out your beloved theory or trying to build it up from scratch based on solid scientific evidence to support each individual tenet. I think the latter is what needs to be done, but it will take time. We need to re-figure out what we know absolutely. IOW, what aspects of special relativity are not contradicted by a CPT violation? If the Lorentz Transformation is called into question then so is science fiction's much beloved time dilation And what about the Twins Paradox? Yikes.

Time dilation has been observed in a number of different contexts, most famously by putting atomic clocks on airplanes and measuring the resulting slow down as they fly around the globe. Even if SR fails, time dilation is still an experimentally verified fact.

Even if SR fails, time dilation is still an experimentally verified fact.

Ah. Good point. Forgot about that. But that's exactly what I mean. Even if we can no longer trust the complete special theory, we can at least trust the parts that have been independently verified by experiment.

Lorentz covariance means that a quantity changes in a way given by the appropriate Lorentz transformations under boosts or rotations. Lorentz invariance means that a quantity is unchanged under boosts or rotations. So, Lorentz invariance is a subset of Lorentz covariance which applies to frame-independent quantities like proper time, electric charge, or rest mass.
As for explaining these results, I think you'll find that a large majority of particle physicists (both theorists and experimentalists) will t

It's only once everything of this sort has been ruled out that we face the prospect of actual, honest-to-goodness CPT violation.

Fair enough. But this has my heart beating a bit harder than usual. Just what exactly are the implications if this is in fact a genuine CPT violation? I've always wanted to be alive during a great scientific revolution. Although this would be very exciting I'm not sure any good would really come of it. It seems that it would just make things more confusing, at least until someone could clean up the mess. 21st century science has become so, well, complacent. No one really expects any more major changes to ou

One thing I've heard is that antiparticles are mathematically equivalent to normal particles moving backward through time if you work the equations all through. If you have an antineutrino that has a different mass than the corresponding ordinary neutrino that means this no longer works. Things shouldn't change mass if you have them travel in the opposite direction through time.

It seems to me that general and special relativity, which deal with the relationship between mass, energy, space and time, would

From the article, "there’s a 5 percent probability that the two types of particles weigh the same." Except, that would require a Bayesian statistical analysis and a prior. The thing to remember about confidence intervals is that the interval is random while the true value is stationary, so if you want to make statements about randomness, you have to make statements about the interval. Example, "An experiment conducted this way would find more muon antineutrinos than muon neutrinos disappear 95% of the time."

The correct statistical statement here would be that an experiment like this one would show a splitting between particle and anti-particle properties at least this large 5% of the time even if there were no difference at all.

You gave a misleading confidence interval interpretation. Your statement disregards the magnitude of the observed effect.

It's likely wrong too - the correct statement is almost certainly something more like "An experiment conducted this way would find more muon antineutrinos than muon neutrinos disappear X% of the time, more muon neutrinos than antineutrinos disappear Y% of the time and the observed numbers are equal Z% of the time," where X+Y+Z = 100, X = Y and X,Y >> Z. X = 95 is not a solution to

I would agree with this statement if you append your original statement to say "An experiment conducted this way would find more muon antineutrinos than muon neutrinos disappear 95% of the time, if our experimentally derived parameters are exactly correct." If no such assumption is made, you can't make any statement about how often an experiment would find a discrepancy. If, for example, there were no actual discrepancy, the experiment would only find one 5% of the time. In other words, while the true value is stationary, both the experimentally derived value and the confidence interval are not.

Quick! Prepend "A means of..." and append "...on the internet." to this statement and patent it!

Here are three things I see to be a consistent form of trouble. First, obviously as we exist, there was not an equal amount of matter and anti-matter created at the big bang. Furthermore most kludges that have been devised to explain this discrepancy have been less that stellar and have tended not to match real data very well, unless they have been tweaked to arbitrarily match real data.

Second, we think there are infinities in the universe, and infinities tend to be catastrophic in the real world. In fact, classical mechanics met it's catastrophe in an infinity. It is unlikely that all the infinities that are created between quantum mechanics at the atomic scale and relativity at the universal scale can simply be normalized out, and black holes are not going anywhere until general relativity is fixed.

Then of course we havethe hacked dark matter née aether to make everything work out and match the theory. In light of these three things, any new data, especially new data the violates current theories, are not problem buy jewels. Jewels that will help us refine, and supposed depose, old theories. It is why we still train scientists, and laught at those that think the world is so boring that there is nothing left to be discovered. Fortunately for those that are curious, nature has new surprises every day. I would hate to live in a world where the special theory of relativity was gospel. Such a world would so boring that I would probably be thinking not of what wonders will come, but how life can be ended.

there was not an equal amount of matter and anti-matter created at the big bang

How do we know? Have we counted the atoms? Maybe the reckoning is still in the future. We know the universe has large scale structure, we can see it in the CMB. Maybe the antimatter is just not close to us.

If the universe contained areas of matter and areas of antimatter, you would see annihilation radiation at the boundaries. I think (not completely sure) that would be detectable for a wide variety of different sized regions. As another poster points out, it would be difficult to explain such a separation without introducing new physics.

Then of course we havethe hacked dark matter née aether to make everything work out and match the theory.

Dark matter is no more a "hack" than expolanets around stars with slight wobbles are "hacks". Omigosh, you need a planet there to "match the theory"! Or is the planet a prediction based on observation and an already well-working theory? Yes, that's what it is. We use the theory of gravity to infer the existence of masses.

People have tried to modify the theory to avoid having to infer mass in pla

There's always the possibility that this is just a variation of the Heisenberg uncertainty principle at work. Maybe it all works, we're just gumming it all up by trying to be "God".

No, I'm not saying we shouldn't try, just that we may discover we're the variable.

I remember going crazy troubleshooting a circuit with an O-Scope and the freakin' thing would more-or-less work while I was monitoring the signals. Turns out it was a capacitance issue and the probe was introducing enough capacitance to make it work, but not consistently and seemingly 'random' - but really depending upon the relative position of the scope probe and how close to the tip I was choking it when measuring. Ever since then I've had a real appreciation for Werner:).

Or it could always be some error in the experiment. While not particularly cogent, I do recall one time in biology doing a bacterial culture and ending up with precisely zero colonies of bacteria the next day. It's possible to happen, but it's kind of tough to keep it that sterile by accident.

It could also just be a random chance. A 1/20 chance isn't really that far fetched, I'd be somewhat more concerned if they had it down to a 1/1 000 000 chance that something was up.

This is like big boy electronics rookie mistake 101. Definitely not college electronics 101, as the latter is a rather useless exposition of the former. Read up on some Jim Williams's application notes from Linear Technology [linear.com] -- it's all there. That's how you do experiments in electronics. Pretty darn carefully, checking yourself at every step. JW's app notes in their entirety a required reading for anyone striving to be good at electronics.

I would like to hope that these anti particles really are understood but my guess is that there is so much that is unknown that any conclusions are really shaky. Perhaps they just relocate to the absolute elsewhere without leaving a clue in their wake.

If the interactions of particles are thought of as a movie, CPT symmetry requires that whatever physics occurs during the show must be the same whether the film is run forward or backward (time), viewed through a mirror (parity) and repopulated with each particle being replaced by an antiparticle (charge).

This is unclear at best. CPT symmetry says that when the film is run backward AND seen through a mirror AND all particles are replaced with the anti-particles (and vice versa) then the physics should be the same.

If you change just one, for example by running the film backward but without the mirror or the the particle exchange, or if you change two, for example, running the film backward and with the mirror but no particle exchange, then the physics will change.

This article confuses things a bit, I think, in saying that this represents a problem for SR (or even GR).

SR say that the speed of light is the same in all frames of reference; that, in fact, is all it says, when you get right down to it. The principles of relativity, homogeneity and isotrpoy are assumed in both classical mechamics and QM as well, mostly, I suspect, because we can't really see why it should not be the case.

Where the problem is, really, is in QM - things like anti-particles are QM constructs, and so is the assumption that they weigh the same as their counterparts; the apparent observation, that anti-neutrinos have another mass than the neutrino, is very surprising for quantum mechanics and does not fit very well into the currently accepted theory.

Perhaps it is not so strange that QM may begin to show some cracks; SR and GR make very few assumptions about anything compared to QM. It is very hard indeed to see where one could sensibly make some changes, whereas is QM, there are so many little nooks and crannies where something murky could be hiding.

With the amount of data collected so far, there's a 5 percent probability that the two types of particles weigh the same

As someone pointed out, this merely means that assuming the masses are the same 1/20 experiments will find similar results due to measurement error. Considering how much data there is to back special relativity, I'm not the least worried about special relativity. I'll start paying attention when the error margin drops to one in a million or something. Seriously, using a 5 percent error margin for something that contradicts a fundamental law of physics is just ridiculous. Oh, and I measured some forces and a